Archaeologists have discovered what appears to be a subterranean Iron Age structure, known as a souterrain, in an Orkney field.

The find was made when the field was being seeded for barley. At first it was believed to be a Bronze Age cist burial, as others have previously been uncovered nearby, but subsequent examination has revealed it to be an Iron Age souterrain or earth-house.

Dr Allan Rutherford of Historic Scotland said: “Preliminary investigations by staff from Orkney College Archaeology Department have shown this to be a souterrain, rather than a cist burial as was initially thought. This example seems to conform to the Orkney form, with a long narrow passage and an oval chamber at the inner end. Structures like this are believed to be have been used essentially as storage cellars and were usually associated with above-ground houses.

“What is exciting about this find is that there have only been a few souterrains excavated in Orkney in recent years. This excavation will hopefully shed further light on their function and use, as recent research suggests that such structures were more important to Iron Age communities than has been so far recognised.’

Historic Scotland is funding the project, which is expected to last around three weeks.